Revolving spring tooth harrow



Oct. 21, 1952 i D. CALKINS 2,614,375

, REVOLVING SPRING TOOTH HARROW Filed July 12, 1948 4 Sheets-Sheet 1 IN V EN TOR.

Oct. 21, 1952 D. L. CALKINS REVOLVING SPRING TOOTH QHARROW Filed July 12, 1948 4 Sheets-Sheet 2 Oct. 21, 1952 D. CALKINS REVOLVING smug 'room HARiROW 4 Sheets-Sheet 3 Filed July 12, 1948 I INVENTOR. ag/Z: L. caaw BY M 947% Patented Oct. 21, 1952 r vmivownvd SPRING 'roo'r r m nnow Dwight L.?Calliins, Spokane; Wash assignor to Calkins 'Manufacturing Company, .Spokane,

Wash a corporation of Washington c Application .iul'y'iz, 1948, Serial No. 38,303 r 3- Claims. (01. 55- 11);

The present invention relates to improvements in a .ievolvingfspring tooth harrow.

Spring tooth harrows'a'r'e quite widely used as a means ofcultivating the soil, and destroying the 1 growth "of weeds. These harrows however,"pre sent 'quite ajproblem where the trash onthe soil is f'airlyfhe'avy. It is desirable from th'e'standpoint of soil conservation to keep the trash'such as stubble and dead vegetation of various types, evenly distributed on the surface of the soil. This material deteriorates gradually toenrich the soil by adding humus thereto. It is particularly useful in preventing erosion since it acts to absorb rainfall and to slow down the run off of water by f damming off the tiny streams which start the soil erosion. It is the purposeof the present invention to provide a novel springtooth harrow wherein the spring teeth rotate, as they are dragged through the sdiL'aJnd-clarise themselves of the trash ina' steady uniform manner to leave the trash spreadevenly' over the soil. a

More particularly itis the purpose ofthe-pres- Figure 1 isa plan view embodying my invention; s

Figure 2 is alongitudinal sectionalview taken.

, substantially on the line 22 of Figure 1;

ent invention toprovide aspringtooth harrow embodying a frameworkin which one or more cross-shafts are rotatably mounted, the shafts having'spring teeth affixed thereto in longitudinally spaced groups, each group including'several teeth arranged about the shaft as 'a center, to-

gether with a retarding device operable to oppose rotation of thespringteeth and the-shaft that would normally becaused. by the teeth engaging the soil; The retarding means is of such a nature that it will retard rotation of the shaft at any v desired rate. As the teeth rise out of the soil due to their rotative movement, they shed the trash individually.

It is also a purpose of this invention to provide a novel combination of rotatably mounted shafts with spring teeth thereon and additional cleansing fingers'whereby the forwardshaft has its spring teeth cleared of trash by the following shaft and the rearward shaft has its spring teeth cleansed of brush by fingers supported on the frame of theharrow and extending between the spring teeth. F 7

Other and'more details and objects of the invention will 'appear'from the following descripnon and accompanying drawings wherein a pre-f ferred'form of the invention isjdisclosed. It should be understood however, that the drawings and description are illustrative only and, should not be considered as limiting the invention except insofar as it is limited by the claims.

a 'In the drawings:

Figures 3 and 4 are enlarged fragmentary sectional views taken on'the lines 3-3 and 44 of Figure -1; and v Figures 5, 6 and 7 are detailed sectional views illustrating the inner construction of the retarding device utilized for retarding the rotation ofthe shafts carrying the spring teeth.

Referring now in detail to the frame 10 which has a draw bar I l secured theretofor attachment to a tractor or other power'vehicle. The frame I0 is supported atthe' proper level with respect to the ground by two wheels [2V and I3, one at each side of the frame. Each;

wheel is mounted upon a lever arm l4 which-is fixed on a shaft 15. in bearings I 6 and I! that are secured to the frame 10. Midway between the sides of the frame I B, the shaft 15 has a lever arm l8 thereon which is coupled to the frame by anhydraulic; coupling 1 9 so that it may be adjusted to hold the; frame at the proper angle with respect to the wheel lever arms to keep the frame H! at the desireddistance from the ground. The hydraulic coupling l9 preferably includes a piston 20, a

cylinder 2| and afluid supply line 22. Fluid for thishydraulie coupling may be from asource of fluid under pressure, not shown, on the tractor. 1

The frame l0 carries twotransverse shaft ,23

and 24 which are journalled in bearings not shown thatare mounted to the underside of, the

frame. The forward shaft 2,3 has a'series of hubs 26- seouredthere'to at spaced intervals be tween the sides of the frame l0. Likewise the rear shaft/ 24 has a series of hubs 21 secured thereto at spaced intervalsbetween the sides of The hubs 2! on the shaft 24 are" staggered with respect to the 'hubs 261onYthe Each of the hubs ZBfand 21 mounts. The haf s and-2.4? are spacedapart a distance slightly greatertha'n' the radial extent of the springteeth 128st; that the teeth carried by the shaft 23 over'lapwith the the frame In.

shaft 23. several spring teeth I 28.

teethcarriedbytheshaft24 y The shaft 23 has a sprocket wheel 29 fixed thereto. A similar sprocket Wheel 30 is fixed "on the shaft 24.

nected by sprocket chains 3| and 32 respectively,

to sprocket wheels 33 and 34 which are provided on the ends of a shafttll that'isfpartte are:

tarding device 36.'

of a springtooth harrow 1 drawings, the spring tooth harrow iscomposed of 'a' rectangular The shaft I5 is 'journalled These sprocket wheelsarejco'n tarding device however, each tooth :of the harrow can be made to drag through the soil a desired distance while it is turning about the shaft,

the same direction as the wheels which, support the frame I0, but, at a slower ratethan'the wheels turn. This retarding device." determines or governs the rate of rotation of the shaftsa23- and 24, independently of the rate at which thehar'row 5 moves across the field.

The details of mounting the hubs 26 and 21"on" their respective Shafts and the mounting of the spring teeth 28 on the hubs are illustrated by Figures 5 and'6 of the drawings; Each-hub-comprises a disc like casting whi'chhas aprojecting' semi-circularxseat 38 on -one.--face-thereof, the

casting is zapertured to.receive-theshaft.v The seat 3 8 has two lugs" 3 9 and 4 0' extending radially of the-hub. The. shaft 23'is secured to the seat 38 by an U-shaped securing member a,the ends of gwhichrextend through the lugs-39 and 40-fand arethreaded to receive nuts 4 I and 42".: An arcu ate strip 143 is inserted-between the member 40- and the shaft.

On theopposite face of-the -hub 26 a seat- 44,

similar. 1to the=seat38 is provided. This seat 44 iSi'HlSO clamped-to the shaft 23 by lugs 45 and-46,

and; u-shapedbolt .41, nuts and 48-randan ar'cuate-stripgSO; This face of the hub-26= has a series of arcuate flanges 5I- projecting outwardly tow'the'rimof the hub. The spring-teeth-ZS are seeuredto the flanges 5 l b-ya bolt 52- and a .nut.

53. Each-flange 5|isreenforced near thefrim.

of1 theuhub. 23 by aweb 54.

The retardingdevice 36 is constructed similarlyto the ---.I-Iydraulic Power Transmission .Device---- shown in the application of Morris 7 -W. .Guyer,

Serial Number 14,935,-filed March 15, 1948.- The shell 55 of-this deviceisstationary -while.the inner element.- 56-mounts the shaft 35 on which thessprocketwheels 33 and 34 arelocated- Adjustment of the rate of retarding is accomplished by-meansof a-hand screw lilwhich advances a valve member 51 that closes aby-pass 58 around-i the vanes.59..- The rate. offlow of liquidthrough the by-passdetermines-the number of rotations of-athe shaft 35 per minute so long as pressureis applied by the. vanes 59 on the liquid. It is believed to beunnecessaryto further describe the 1 details: of this device since. they are fully dis-fv r closed inthe'prior application referred to above.. Any other'adjustable retarding device for-governe application identified above, is particularly use-.. ful for my purpose since it provides asimple ef-T fe'ctive means for governing the rate of rotation of .the .springrteethon the .shafts23 and 24' that has-no :brakingaifect on the wheels supporting the device.

The rear-.framemember IOaLof the frame. It

alsoflcarriesaseries.of fingers. which extend forwardly between the teeth on the shaft.'

Thesefing'ers serve to remove any trash that may have atendencyto cling to the spring teeth.28.

on' the rear shaft? The number of spring teeth 28 on;each hub may.

vary. Better results are obtained in shallow cultivation with a greater number of teeth. The angular spacing of the teeth should be such that, as the hub turns, the tooth that is moving down enters the soil a substantial depth before the rising tooth leaves the soil.

In operation a rotary spring tooth harrow embodying -my.in.vention has the distinctadvantage that any trash caught by the teeth on the forward shaft while they are in engagement with the soil, iswiped off by the downwardly moving teeth on the rear shaft in a uniform continuous operation. Likewise-the teeth on the rear shaft are caused toshed the trash continuously as they rise from .:the soil... lnzthis way the trash is distributed continuouslyoverthesoil as the cultivation takes place. If the trash is bunched before harrowing, the present invention tends to spread the bunches to give ;a more uniform and even distribution of the trash on the surface of the soil. The Wiping actionof the inter-meshed spring-teeth on the forward and rear shafts and the wiping. action of the fingers .60 also contribute to. even distrilnition.of the trash so that ,itis' spread .overth'e 'surface'after the cultivation has taken place...

It is believed that-the nature and .advantages' of the. present. invention will" be apparentllfrom. the foregoing. description. Having thusdescribedl my L invention, I .claim:

1..A rotary spring .tooth harrow .comprisinga. frame, means. .to support the -frame .above the ground, means for attaching the-frame toa pull! ing. device, a shaft. extending. transversely of said. frame and rotatably,mounted .-thereon,-.springt.

teeth secured .to. said. shaft,. said: teeth ,beingv spaced apart lengthwiseand circumferentially off:- the shaft, whereby engagement of the teeth with.- the ground, as the. harrow isvdrawn'vforward; exerts a .force tending- -to turn the shaft :so that-n. the teeth inrear of theshaftrise=andtheteetlr in front of the shaft move down,.fingers on-said'.-; frame to the rear of the shaft extending-forward- 1y betweenlaterally adjacent. spring teeth; acting '7 45 to strip trash fromthe rising teeth; and a;retard-:

ing. device 'operably; connected-:with said -shaft. limiting its rotation; ,by said force. -to'a 'prede-ltermined rate.

2. A. rotary spring-tooth harrow 'comprising ar'. main frame, supportsfor the frame, 'tWo'xspaoed apart shafts extending 1 horizontally. across: =.th'e frame, means rotatably mounting rthe 'shafts to the frame, spring .tooth mounting ;.hubs fixed on; each. shaft, .the hubs being spaced apart lengthwwise of each shaft, the hubs on one shaft being Staggeredwith respect-to those on the adjacent: shaft, spring teeth on each hub and-angu1arly spaced about the shaft as an axis, a retarding device mounted on the frame-including- -a shaft.v means positively connecting. saidshaft? to: the"? first named. shafts .to cause the shafts torotate in unison, and -meansgoverning the rateof rotation of said last named shaft.

3. A rotary spring. tooth harrow-.comprising;a frame,-. means to support the frame above 1131161; ground, means for attaching the frame 24 pulh; mg -.device, two shafts extending :transversely. of said frame and rotatabl mounted thereon, springteetli secured to each. shaft,. said teethbeing z spaced apart lengthwise and circumferentiallylofe the shaft, whereby engagement of the.teeth:with--.- the ground, as the harrowis .drawn. forward. ex; erts a forc'etending-to turn..the.shaft.so that the;- teeth in rear of the-shaft. rise and-the teeth invfront of the shaft move down, theeteethinrrear of the front shaft being intermeshed with the teeth in front of the rear shaft, and a retarding device operably connected with each shaft limiting its rotation, by said force, to a predetermined rate.

DWIGHT L. CALKINS.

REFERENCES CITED Number The following references are of record in the 10 Number file of this patent:

UNITED STATES PATENTS Name Date Miller Jan. 9, 1906 Cody Apr. 22, 1919 Gefiroy Feb. 24, 1931 Kaupke Feb. 9, 1932 Peacock Dec. 21, 1937 FOREIGN PATENTS Country Date Denmark July 1'7, 1944 

